1. Field of the Invention
The present invention relates to counting scales and counting methods, and in particular, to the weighing of articles in order to derive a count.
2. Description of Related Art
Articles are often counted before being packaged and delivered. For example, common elements such as bolts may be counted before being priced/packaged and sold to a customer. Such counting ought to be done accurately, but can be monotonous and prone to errors when done repetitively.
Many different techniques exist for counting objects, from doing a visual examination, to establishing a unit weight and then making a measurement of the overall weight (optionally correcting for the tare) in order to deduce the count by dividing the overall weight by the unit weight. A related method employs a scale to weigh a single item and then enter that value into the scale memory for future use when determining from a cumulative weight the number of like-weight units being weighed.
Weighing scales may be produced using existing microprocessors that connect to a Wheatstone bridge. See application notes AN780 (2002) and AN1030 (2006) by Microchip Technology, Inc.
In a pharmacy, pills are routinely counted to fill a prescription that specifies a given number of pills. The counting must be done accurately not only because medications can be expensive, but because delivering the wrong number of pills can have adverse health consequences to a patient that ends up taking an insufficient or excessive number of doses. For pill counting, devices exist that permit pills to be counted by various means of filling a cavity and by mechanical techniques such as sweeping a count location volume to ensure that the correct number of units has passed.
A currently popular method of counting pills employed by pharmacists is to use a small plastic tray-like platform to support pills where they can be spread out on a relatively sterile environment and counted with a scalpel-like blade, which is used to sweep the pills.
After a quantity of pills is placed on the tray's platform, a blade may be used to successively sweep small numbers of pills into an adjoining trough while the pharmacist keeps count. Subsequently the tray is tilted and the lower end of the trough then serves as a partial funnel to guide the pills into the retail container.
See also U.S. Pat. Nos. 4,157,738; 4,398,613; 4,447,885; 4,493,384; 4,512,428; 4,629,016; 4,646,767; 4,674,060; 5,199,517; 5,608,193; 7,073,707; 4,646,767; and 6,884,946.